In a photolithography process of forming a resist pattern on a semiconductor wafer (hereinafter, referred to as a wafer) that is a substrate, heat processing is performed on the wafer using a heating device (heating module). The heat processing may be, for example, a process called as post exposure baking (PEB), by which after a resist film is exposed along a predetermined pattern, a wafer before development processing is heated. The heating device is configured to include, for example, a heat plate that heats a wafer mounted on the heat plate. There is known a heating device including the heat plate.
However, the heat processing may be performed in astute in which the wafer is transferred to the heat plate in a state in which a foreign substance exists on the heat plate or is attached to a back side of the wafer, so that the wafer is placed on the foreign substance interposed between a surface of the heat plate and the back side of the wafer. In this case, distances between the surface of the heat plate and the back side of the wafer at in-plane portions of the wafer are different from each other, and therefore, temperatures of the in-plane portions of the wafer may be different from each other. As a result, critical dimensions (CDs) as dimensions of the resist pattern at the in-plane portions of the wafer after development may be formed differently from each other.
In the type of heating device that has already been described, it is detected whether abnormality has occurred in the mounting state of a wafer, based on a profile of changes in the temperature of the heat plate when the wafer was mounted on the heat plate. However, if the height of a foreign substance is relatively small, a difference between a temperature decrease in a region in which the foreign substance exists on the heat plate and a temperature decrease in another region of the heat plate is small, and hence it cannot be detected whether the water is placed on the foreign substance. Therefore, it is impossible to accurately determine whether an abnormality has occurred in the CD.